Brake



Sept. 25, 19 34. H. F. PARKER BRAKE Filed May 17, 19:50

m w I E V a m z w x; W m m M W a A TTORNEY Patented S ept. H

)1 UNITED STATESIIPATENT OFFICE 1,974,582 "BRAKE" Y Humphrey-F. Parkefifiouth Bend, Ind., assignor to Bendix Brake Company, South Bend, Ind., a

corporation of Illinois Application lt1ay 17, 1930, Serial No. 453,386 qs'ouim. (01. 188-78) This invention relates to brakes and more partlcularly to internal expandingbrakes.

It is well established that if two fiat surfaces are'brought' in contact with each other, the fric- 5 tionbetween them is the product of the pressure forcing them together and the coefficient of the friction of the'surface. In a brake shoe, the frictional forceis dependent not only upon these factors, butalsok upon the angle of approach-which diilersat different points of the shoe surface.

-"It is the aim of the present invention to pro- I vide a structure wherein the pressure is applied to the brake shoe in such a maner that it will more perfectly conform to a rotatable drum.

A major object of the invention is to provide means for applying the frictional members so that they will perfectly conform to the drum.

Another object of the invention is to provide means for applying the frictional members at points removed from the respective ends of the frictional members.

Yet a further object of the invention is to provide a suitable structure for applying the frictional members, so that they will perfectly conform and that the respective ends of the frictional members will perform as efiiciently as other portions of the frictional members.

A feature of the invention is to provide a friction member with pivotal links arranged in spaced relation from the respective ends of the member, so that the member may be uniformly applied to a rotatable drum.

A further feature of the invention is to provide a brake which has the advantages of positive ap-, plication of the frictional members, a brake which is highly eflicient in operation and yet of marked simplicity as a whole in respect to each of its component parts, so that its manufacture, ma be economically facilitated both as regards to parts and their assembly.

Other objects of the invention will appear from the following description taken in connection with the drawing, which forms a part of this specification, and in which:

Figure 1 is a side elevation of a brake illustrat-' ing the invention as applied,

Figure 2 is a sectional view substantially on line 22, Figure 1,

Figure 3 is a sectional view substantially on line 3-3, Figu Figure 4 is a modified form of the invention, and

Figure 5 is a sectional viewvsubstantially on line 5-5, Figure 4.

In the embodiment illustrated, there is provided a conventional rotatable drum 10 at the open sideof which is a stationary support such as a.backing;plate 11. Positioned onthe backing plate'areanchors 12 and 13 and steady rests 14 and 15 11 ;l ounted for movement on the plate is aprima y-shoe .-1ogand a secondary shoe 17. As shown,,.= shoes'are interchangeable. and. eactrtcomprises s rim 18 towhich is suitably, cured a-lihih'g 19 adapted to eng ge the drum" andfajpfiange 20 cut away as at 21 and 22 to lend'flexibility to the shoes.

Although this particular type of shoe is described, it is to be understood that applicant in no way limits his invention to this precise form,- as other forms of shoes may be used with equally good effect, provided; the rim is sufliciently flexible to conform to the radius of the drum.

The articulating ends of the shoes have a web portion 23 apertured to receive the respective steady rests 14 and 15 and these web portions are connected by a suitable adjusting screw 24 of any preferred type.

Due'to the cut away portions 21 and 22, there is formed in spaced relation to the other end of the primary and secondary shoes a web portion 25 to which is pivotally secured, as by a bolt26,

a link 27 apertured to receive the respective anchors 12 and 13 and having rounded shouldered portions 28 and 29. As shown, the links 27 are connected by a coil spring 30 and the primary 8,5 shoe is connected by a coil spring '31 to a fixed support 32. These springs serve to "returnthe shoes to the off position. j

Positioned between the shoulders" 28 and '29 of the shoes is a cam 33 operablegthr'ough a shaft 3d.- The cam is provided with-rotatable members;}35and 36 adaptable for engagement with the shoulders 27 and 28 upon the primary and secondary shoes.

In Figure 4, I have shown a modification wherein the spring 30 is connected between shoes of a rigid type. In this embodiment of the invention the angle of approach is sufficiently removed from the toe of the shoe to cause the respective ends of the shoe to engage'the drum with substantially equal elfect asother portions of the shoe.

, Upon"actuating the cam 33 to spread the shoes apart for'engagement with the drum 10, the force of application of the shoes is at a point spaced from the ends adjacent the anchors. Hence, a more uniform application of thefrictional 'members to the drum may be attained;

Although this invention ha'sbeen described in connection with certain specific embodiments. the 116i connecting the "articulating ends of the shoes,

links pivoted on the shoes in spaced relation from the other ends of the shoes,,anchors engaged by the links, shoulders on the links, a cam positioned between the shoulders and a coil spring connected between the shoes.

2. A brake having a drum and friction meanscomprising two anchorages forming the ends of said friction means, one eifective when the drum is turning in one direction and the other effective when the drum is turning in the other direction, one of said anchorages being constructed and arranged to permit radial movement of the adjacent portion of the frictionmeans, and an applying lever having parts in disconnected thrust engagement with the ends of the friction means and operative to pry said ends apart to apply the brake. 3. A brake having a drum and friction means comprising two anchorages forming the ends of said friction means, one effective when the drum is turning in one direction and the other effective when the drum is turning in the other direction, both of said anchorages being constructed and arranged to permit radial movement of the adjacent portion of the friction means, and an applying lever having parts in disconnected thrust engagement with the ends of the friction means and operative to pry said ends apart to apply the brake.

4. A brake having a drum and friction means comprising two anchorages forming the ends of said friction means, one effective when the drum is turning in one direction and the other effective when the drum is turning in the other direction, one of said anchorages comprising a pivoted link :permitting'the adjacent portion of the friction means to-shift radially, and a floating applying lever having thrust parts in direct disconnected thrust engagement with the ends of the friction means and operative to pry said ends apart to apply the brake.

5. Abrake having a drum and friction means comprising two anchorages forming the ends of said friction means, one effective when the drum is turning in one direction and the other effective when the drum is turning in the other direction, said anchorages comprising pivoted links permitting the adjacent portions of the friction means to shift radially, and a floating applying lever having thrust parts in direct disconnected thrust engagement with the ends of the friction means and operative to pry said ends apart" to apply the brake. i

' -HUMPHREY F. PARKER. 

